1. Field of the Invention
The invention relates to a male terminal fitting having a tab at its front end and to a method of forming it.
2. Description of the Related Art
A male terminal fitting having a tab at its front end is formed by bending a metallic plate of uniform thickness. It is desirable to thin the metallic plate to reduce the cost and weight. However, a necessary thickness is specified for the tab, and the specified thickness of the tab may be twice the thickness of the metallic plate.
U.S. Pat. No. 5,681,192 and FIG. 11 herein disclose prior work by the assignee of the subject invention to accommodate such dimensional requirements. As shown in FIG. 11, a tab 100 of the male terminal fitting has a substantially flat plate 102 formed at the front side by folding left and right sides of a metallic plate in and opposing free ends 101a of folded portions 101 to each other. A plate 103 at the rear side has a bulge 104 and a supporting projection 105 of the bulge 104 contacts the front plate 102.
With this construction, the tab 100 may be twice as thick as the metallic plate by taking a double-layered structure by the front and rear plates 102, 103 and forming the rear plate 103 with the bulge 104. The strength of the tab 100 may be reduced since the bulge 104 defines a space between the front and rear plates 102, 103. However, a sufficient strength is secured for the tab 100 by bringing the supporting projection 105 at the rear plate 103 into contact with the front plate 102.
The tab 100 is made transversely symmetrical for a sufficient strength and since a terminal main body (not shown) extending back from the base end of the tab 100 is transversely symmetrical. Thus, the two folded portions 101 at the front side, the bulge 104 and the supporting projection 105 are formed transversely symmetrically, and the supporting projection 105 is at a position where the free ends 101a of the folded portions 101 are opposed to each other.
The supporting projection 105 is at a position where the free ends 101a of the folded portions 101 are opposed to each other. Thus, a pressing force on the rear plate 103 may thrust the supporting projection 105 between the free ends 101a to deform the front plate 102 in a manner to separate the free ends 101a. 
The present invention was developed in view of the above problem and an object thereof is to provide a male terminal fitting which can prevent a deformation of a tab.
The invention relates to a male terminal fitting formed with a double-layered tab by bending, folding and/or embossing a conductive plate. The tab comprises a first plate and a substantially flat second plate formed by substantially opposed free ends of two folded portions folded inward substantially along widthwise direction at the left and right edges of the first plate. The first plate is formed with at least one bulge spaced apart from the second plate and supports projecting from the bulge toward the second plate and held substantially in contact with the two folded portions at positions displaced toward side edges from the free ends of the two folded portions.
The opposed free ends of the two folded portions may be held in contact with each other or may have a clearance therebetween.
The tab could be weaker due to the space between the two plates. However, the supports projecting from the bulge are held in contact with the second plate. Therefore, a sufficient strength is secured for the tab.
The supports contact the second plate at positions displaced toward the side edges from the free ends. Accordingly, the supports cannot thrust move between the free ends even if a pressing force acts on the first plate in a direction toward the second plate. Thus, the tab is not likely to deform.
The first plate preferably is formed with a substantially flat portion to be held substantially in surface contact with the two folded portions in a continuous area including a position where the free ends of the two folded portions are substantially opposed to each other. Accordingly, a pressing force on the first plate is dispersed in the flat portion and acts on the second plate, and a concentration of stress on the second plate can be avoided.
The left and right edges of the flat portion preferably are continuous with the supports. Thus, the supports and the flat portion form a substantially U-shaped cross section. Accordingly, the shape of the first plate portion is simpler than a case where the flat portion and the supports are separate.
The rear end of the tab may be continuous with a transversely symmetrical terminal main body, and/or the free ends of the two folded portions are opposed substantially at a widthwise center of the tab and the supports are substantially equidistant from the opposed position of the free ends. Thus, there is no danger that only one of the left and right sides will be deformed during formation of a portion coupling the tab and the terminal main body. Accordingly, the concentration of a stress can be avoided.
Two bulges preferably are provided in the first plate spaced along the widthwise direction and have an intermediate plate therebetween.
The intermediate plate preferably is spaced from the leading ends of the folded portions.
The invention also relates to a method of forming a male terminal fitting with a double-layered tab. The method comprises providing a conductive plate. The method continues by bending, folding and/or embossing the conductive plate to form a tab with a first plate and a substantially flat second plate such that opposing free ends of two folded portions are folded inward along a widthwise direction at the lateral edges of the first plate. The method then includes forming the first plate with at least one bulge spaced apart from the second plate and supports projecting from the bulge toward the second plate and held substantially in contact with the two folded portions at positions displaced toward side edges from the free ends of the two folded portions.
The step of forming the first plate may comprise forming a substantially flat portion to be held in surface contact with the two folded portions in a continuous area including a position where the free ends of the two folded portions are opposed to each other.
Preferably, the rear end of the tab is formed to be continuous with a transversely symmetrical terminal main body.
These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments.